How many stars does a spiral galaxy have?
How many stars does a spiral galaxy have?
It is the dominant member of a small group of about half a dozen galaxies, the M74 galaxy group. In its entirety, it is estimated that M74 is home to about 100 billion stars, making it slightly smaller than our Milky Way.
Do stars form in spiral galaxies?
The spiral arms in spiral galaxies are one type of environment where gravity is pushing gas and dust to form stars more efficiently than in other parts of a spiral galaxy. This is why you see more star forming regions and collections of young stars (open clusters) in spiral arms than in other parts of a spiral galaxy.
How do stars move in a spiral galaxy?
Our Galaxy, like all other spiral galaxies is rotating. The stars move on orbits around the centre of the Galaxy. Stars also have some random motions – they don’t orbit the galaxy in exact circles. This random motion usually amount to a few tens of km/s in some direction.
Where is star formation in spiral galaxies?
The final aspect of the formation of spiral galaxies is the on-going star formation evident in their thin disks. This star formation is usually on the leading edge of the spiral arms where the cold gas of the thin disk is compressed, and provides unequivocal evidence for on-going secular evolution in thin disks.
Why are stars formed in spiral arms?
Star formation caused by density waves As the compression wave goes through, it triggers star formation on the leading edge of the spiral arms. As clouds get swept up by the spiral arms, they collide with one another and drive shock waves through the gas, which in turn causes the gas to collapse and form stars.
What do stars in a galaxy orbit?
The stars in our galaxy are all orbiting in a nearly circular path around the center of the galaxy. They do this because the immense combined mass of the galaxy, most if it near the center, creates immense gravity that pulls all the stars in our galaxy into circular orbits.
What force holds the stars in orbit in spiral galaxies?
gravity
The inexorable force of gravity tries to pull the stars in a galaxy closer towards the center. The gravitational force is balanced by the orbital motion of a star (like a stone whirled on a string) which generally prevents it from settling any deeper on average into the galaxy.
What kind of stars do irregular galaxies have?
They have no defined shape nor structure and may have formed from collisions, close encounters with other galaxies or violent internal activity. They contain both old and young stars, significant amounts of gas and usually exhibit bright knots of star formation.
